EDH, or Commander, is a format in which consistency is shot. You choose a Legendary Creature as your commander, and try to base a huge Singleton 100 deck off of what suits your Commander. The rules are of course on the internet somewhere, and if you're interested in EDH, please check them out.
My commander is Rakdos, Lord of Riots. RRBB is occasionally a difficult casting cost to play with, and your opponent also has to lose life that turn in order to cast Rakdos. This isn't a bad turn 5, or even a bad turn 6 or 7, being a 6/6 Flying Trample that also makes your creatures cheaper. I pulled him in a pack and knew he was the one. I love the mana amount as well as the big hitter.
Cunning Sparkmage is an amazing turn 3 for this deck, a 0/1 Haste that taps to shoot something for one. Definately good for trying to get the big guy out on turn four. Playing a black EDH of course means lots of tutors. While I haven't gotten the almighty Demonic Tutor, Diabolic Tutor and Diabolic Revelation get me what I need. For those who don't know, to tutor means to get a card from your deck and put it in your hand. Playing a large deck with one of each card makes it necessary for these tutors to be included in the deck. Blessing of Leeches is a great way to keep beating. It gives enchanted creature regen for 0, although you do lose a life at your upkeep. A 3 drop that is often the target of my tutoring, it interacts extremely well with my commander, essentially making it indestructible and there's no need for extra mana when casting again, because it doesn't die.